All Myanmar’s airports are staying closed and no flights will operate for the next few weeks.
Leaders of the military coup said all passenger flights are suspended.
It issued a Notice to Airmen (NOTAM) stating the suspension will last until the end of April 2021.
It includes all flights to, from and within its borders, with the exception of relief flights.
The US Embassy in Myanmar said the access road to the international airport in Yangon has been closed since the beginning of this week.
The US issued a security advisory saying some Internet service is being blocked.
"There is potential for civil and political unrest in Burma, and we will continue to monitor the situation," it said.
Written by Ray Montgomery, Asia Editor